Effects of temperature and Bacillus thuringiensis israelensis on life history traits of Aedes aegypti and Aedes albopictus mosquito species

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SARITA ACHARI, TAPAN KUMAR BARIK This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6635876/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background Temperature changes are common in nature and insects are particularly exposed to such variations which can be potential stresses, ultimately affecting life history traits and overall fitness. Here, we assessed the life history parameters of Aedes aegypti and Aedes albopictus when its larval stages were exposed to high temperatures (39°C, 40°C) and Bti (1 ppm and 1.5 ppm). The effects of both temperature and Bti were evaluated on the treated Aedes (F 0 ) (immediate effects) and on their first generation (F 1 ) progeny (trans-generational effects). Results In the present study, it has been observed that temperature and Bti significantly influence the behavioral traits in both Aedes mosquito species. Temperature stress imparts negative influence on Aedes mosquito by decreasing survival, longevity and reproductive potential while it imparts some positive effects like decreasing developmental period and producing more female offspring which can increase mosquito population and transmission of pathogens. Bti alone affects most of the life history traits beyond the parental generation. However, temperature stress alone and the combined effect of both stress do not affect the life history traits significantly in F 1 generation. Bti exposure increased the developmental period, reduced reproductive potential of the Aedes mosquito in F 1 generation. Conclusions Therefore, it may be concluded that Bti can be used as an effective tool for Aedes mosquito vector control. Temperature and Bti in combination reduce survival rate and reproductive potential in Aedes mosquito. Consequently, it appears that while global warming may cause an increase in dengue transmission, based on the current findings, Bti can be used for dengue prevention and control in the changing climatic condition. Temperature Aedes aegypti Aedes albopictus Bacillus thuringiensis israelensis Life history traits Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Background Climatic changes forecasted in the coming years are likely to result in substantial alterations to the distributions and populations of vectors of arthropod-borne pathogens. The Intergovernmental Panel on Climate Change has predicted 2–4°C rise in mean global temperature over the next century (IPCC 2007) that result in significant changes to ecological landscapes and patterns of infectious disease. In tropical and subtropical countries, people are at risk of infection from many mosquito vector-borne diseases. Aedes mosquito, the vector of dengue and chikungunya is very resistant to different control tactics as it is closely associated with domestic and peridomestic human settings (Reiter & Gubler, 1997). Efficient and commercially viable vaccines are not yet available for these vector-borne diseases. Therefore, the prevention and control of such vector-borne diseases remain dependent on different strategies which include the use of different chemical insecticides to minimize the risk of transmission. Thus, the mosquito control programs unsurprisingly swing towards the use of microbial, phytochemicals and other biocontrol strategies (Lacey, 2007 ). Bacillus thuringiensis subsp. israelensis (Bti) and its derivatives represent a safe and eco-friendly alternative to chemical insecticides for the management of mosquito vector. Many biotic and abiotic environmental factors affect different life stages of mosquito. As mosquitoes occupy holometabolous life, different environmental niches during their immature as well as mature stages are influenced by environmental conditions. The larval stages of mosquitoes are stages that confined to aquatic habitats. The availability of containers in nature determines the micro climatic condition by the larval stages of Aedes mosquito (Alto and Bettinardi, 2013 ). However, the adult stage is highly mobile and daily environmental temperature influenced mosquito activity (Gray et al., 2011 ; Meyer et al., 1990 ; Rowley and Graham, 1968 ; Wright and Knight, 1996). Therefore, change in environmental temperature between two different stages of mosquito such as immature and mature is a common phenomenon in nature. The environmental conditions faced during the development especially the early stages may have strong downstream effects on the life history traits. Further, environmental temperature also influence the immature stages of mosquito to develop the adult phenotype e.g., nutritional reserves (Briegel et al., 2000 ; Briegel and Timmermann, 2001 ; Briegel et al., 2001 ) and may also modify lifespan and susceptibility of adults to the pathogen. Mosquito life history traits, pathogen transmission, vectorial capacity are highly influenced by different environmental conditions, therefore, a better understanding of their response to different environmental conditions especially temperature can lead to more accurate forecasts of disease transmission and the development of new, novel, effective control strategies. Mosquito larvae are exposed to insecticides in the presence of many environmental stressors. Standard toxicological studies are usually piloted in the absence of these environmental stressors which is expected to underestimate the lethal effects of insecticides on mosquitoes. However, insecticide toxicity depends on the type of formulation, insect biology, and the environment in which these interact. Thus, it is difficult to predict how an insecticide susceptibility test in a controlled laboratory condition decodes to the efficacy of an insecticide in the field condition (Glunt et al., 2013 ). Generally, laboratory based experiments give some indication on the effect of temperature by maintaining insects either at different constant temperatures or on different fixed temperature cycles. In nature, ectothermic creatures may experience extreme temperature for a few hours that may cause changes in body temperatures for a very short duration and also induce residual effects that continue even after the temperature returns to its normal condition. Similarly, insecticide is another important factor that may influence the behavioral characteristics and viability of mosquitoes. Aedes aegypti and Ae. albopictus population experience variations in various concentrations of insecticide, which may cause changes in their growth, behavior and development. The influence of a particular insecticide on immature stages of mosquito basically depends on the dose, intensity and duration of exposure of insecticide. High dose of insecticide have a severe impact that kills insects population while low insecticide concentrations in sublethal doses can change in morphological, behavioural, immune, hormonal, and reproductive functions (Rohr et al., 2008 ; Sandland and Carmosini, 2006 ; Weis et al., 2001 ). So, it is important to know the effect of insecticide and temperature individually or in combination on behavioral traits of mosquito not only in exposed population but beyond it in the next generation or in several generations for developing a better control strategy. It is very important to investigate such effects in local strain in response to climate variation. Mosquito populations are most widespread in tropical areas with average temperatures ranging from 25°C to 35°C (Dixit et al., 2002 ), but they still survive in low density in different habitats with such extreme conditions. In India, although for a short duration the average daytime environmental temperature during the summer exceeds 40°C hence, it is critical for larvae occupying habitats exposed to such high environmental temperature (Swain et al., 2008 ). Therefore, in the present study, experiments were conducted to understand how thermal stress and Bti insecticide affect certain behavioral traits of two important mosquito vectors Ae. aegypti and Ae. albopictus . Specifically, investigation were made to understand the effect of thermal stress and Bti on development time, survivability, fecundity, hatchability, sex ratio and longevity of Ae. aegypti and Ae. albopictus . The LT 50 value at 40°C was 62.03 min and 62.05 min for Ae. aegypti and Ae. albopictus respectively and both larvae survived up to 300 minutes exposure at 39°C. The LC 50 and LC 90 value for Bti was 0.931 ppm and 2.23 ppm in Ae. aegypti and 0.835 ppm and 1.968 ppm in Ae. albopictus respectively (Achari et al., 2017 ; 2019). Two temperatures doses (39°C and 40°C) for sublethal period and two Bti concentrations (1 ppm and 1.5 ppm) were taken in the present study. Methods Mosquito and standard rearing conditions Aedes aegypti and Ae. albopictus mosquito were originally collected from different parts of berhampur city (19° 18' 53.8632'' N and 84° 47' 38.7240'' E.) Ganjam District of Odisha State, India and maintained at 25 ± 1°C and relative humidity of 65 ± 5% with 12 hour light and dark photoperiods in an insectary. Larvae were fed with a mixture of yeast powder and dog biscuits in the ratio of 3:2 (Helinski et al., 2009 ). Adults had continuous access to food of 10% glucose solution and raisins soaked in water. Females were blood-fed using artificial blood-feeders, as needed. Late third instar larvae of field-collected Aedes mosquitoes were used to conduct this experiment. Thermal stress assay Late third instar larvae of Ae. aegypti and Ae. albopictus (25 individuals/replicate) were placed in 250 ml of tap water separately and maintained in a thermostatically regulated water bath to observe the effect of temperature as per the guidelines of WHO ( 1988 , 2006 ) at 10 min intervals. This experiment was replicated a minimum of 5 times. Larvae at 25 ± l°C were used as control whereas 39°C and 40°C for a sub-lethal period were used as experimental temperature with the standard photoperiod. The selection of this temperature range was based on a simple algorithm as below and above 40°C which is recognized as the threshold temperature for survival of immature stage and later development (Bayoh and Lindsay, 2004). The temperature of the water having mosquito larvae in water bath was increased slowly in such a way that the temperature will increase by 2°C in 20 min. Live Aedes mosquito larvae were taken for life history study after temperature exposure. Bti bioassay Commercially available Bti was procured from Summit Chemical, Baltimore, USA for evaluation against Ae. aegypti and Ae. albopictus . Late third instar larvae were treated with different concentrations of Bti ranging from 0.5–2.5 ppm as per the guidelines of WHO ( 1988 , 2006 ). Minimum of five replicates of 25 larvae each were taken for Bti treatment. For the life history study, Bti doses between LC 50 and LC 70 (1 ppm and 1.5 ppm) were taken as fewer larvae survived above this dose and thus difficult to execute further study. Bti exposure to thermally adapted Aedes larvae Larvae of Aedes mosquitoes were exposed at 39°C and 40°C for sublethal period (240 min and 60 min for 39°C and 40°C respectively) and were re-exposed to Bti solution of 1.0 ppm and 1.5 ppm. After 24 h recovery, viable mosquito larvae were taken randomly for life history assay. All life history traits such as development time, survivability, sex ratio, fecundity, hatchability and longevity were assessed in treated parent generation and its F 1 generation (untreated). Assessment of life history traits Aedes Larval developmental period - Developmental time in terms of development from first instar larvae to emergence of adults were assessed after treatment to the early fourth instar larva. Survivability rate- Survivability rate was assessed by following larval development from first instar larvae to emergence of adults. Adult sex-ratio - After adult emergence from treated larvae through pupae, females and males were calculated, and the sex ratio (female/ male proportion) was determined. Adults were left for mating in adult cages and used for fecundity and hatchability studies. Fecundity- The fecundity experiments were conducted by taking an equal number of male and female mosquito larvae that had emerged from the control and treated sets. These were placed in individual 30×30 cm cages for each concentration. Three days after the blood meal, eggs were collected daily from small plastic bowls containing water kept in an ovitrap in the cages. Fecundity was calculated from the number of eggs laid in ovitraps divided by the number of mated females. Death of adults in these experiments was taken into account Hatchability - Hatchability was measured in percentage as the number of hatched eggs by the total number of collected eggs after treatment to the early fourth instar larva. Longevity- The adult longevity of male and female mosquitoes (F1 generation) was also recorded. This was calculated as the number of days lived by the adult. Total number of days from adult emergence to death was recorded and the means were calculated to give the mean longevity in days. Statistical analysis Probit regression analysis which the slope, LC50, LC70, LC90 and their 95% confidential intervals (CI) were obtained. The toxicity (ITU/mg) of the Bti product was determined according to the following formula: Potency (Bti product) = LC50 (standard)/ LC50 (Bti product) x potency (standard) Obtained data were analyzed using a one-way analysis of variance (ANOVA) and Two-way analysis to find out interaction between temperature and Bti in life history trait followed by multiple comparisons with Tukey’s HSD to identify statistically significant differences between the treated and untreated (control) group. Results Development time A significant decrease in developmental period in both Aedes mosquito was observed after exposure to 39°C and 40°C respectively. Decrease in development time of 1.6 and 2 days in Ae. aegypti (F 2,12 = 21.00, P ˂ 0.001) and 1.6 and 1.8 day in Ae. albopictus was observed in comparison to control (F 2,12 = 25.750, P = 0.001). However, there was no such significant difference noticed in developmental time in F 1 progeny of thermally exposed Ae. aegypti (F2,12 = 0.783, P = 0.479 ) and Ae. albopictus (F 2,12 =1.130, P = 0.355 ) (Fig. 1 ). Mean developmental period of Ae. aegypti and Ae. albopictus , surviving from larvae exposed to sublethal concentrations (1 ppm and 1.5ppm) of Bti larvicide indicates a non-significant difference (P ˃ 0.05) as compared to control. The developmental period increased non-significantly with an increase in Bti conc. An analysis of the mean developmental time of F 1 of Ae. aegypti (F 2,12 =28.778, P ˂ 0.001 ) and Ae. albopictus (F 2,12 =25.333, P ˂ 0.001), exposed with sublethal concentrations of 1 and 1.5 ppm of Bti indicates a significant increase as compared to control. Two way ANOVA analysis showed the developmental period increased non-significantly in larvae exposed to 39°C×0.5ppm, 39°C× 1ppm, 40°C× 0.5ppm, 40°C×1ppm from control group in Ae. aegypti (F 1,20 = 0.035, P = 0.853) and Ae. albopictus (F 1,20 = 1.225, P = 0.282). However, we observed that developmental period did not differ significantly in F 1 progeny derived from Ae. aegypti (F 2,12 = 1.385, P = 0.288) and Ae. albopictus (F 2,12 =1.103, P = 0.363) treated at 39°C× 1ppm, 39°C× 1.5ppm respectively. Survival rate Survival of Ae. aegypti (F 2,12 = 27.320, P = 0.000) and Ae. albopictus (F 2,12 = 23.326, P = 0.000) decreased significantly to 1 and 1.7 fold at 40°C treatment with respect to control set. A non-significant decrease in survival rate was observed after exposure to 39°C in both Aedes mosquitoes. F 1 progeny obtained from thermally exposed larvae of Ae. aegypti (F 2,12 =2.540, P = 0.120) and Ae. albopictus (F 2,12 =3.450, P = 0.066) showed no such significant difference in survival rate (Fig. 2 ). Significant decrease in the survival rate in Ae. aegypti (F 2,12 = 17.055, P = 0.000) and Ae. albopictus (F 2,12 =31.317, P = 0.000) was observed after exposure to Bti with lower survival at 1.5 ppm of Bti in both Aedes mosquito. A nonsignificant decrease in the survival rate was found in F 1 progeny of Bti exposed Ae. aegypti (F 2,12 =1.896, P = 0.193) and Ae. albopictus (F 2,12 =2.733, P = 0.105). A significant decrease in survival was noticed in both Aedes mosquito after all treatments such as 39°C× 1.5 ppm, 40°C× 1ppm and 40°C× 1.5ppm. However, there was no such interaction found between temperature and Bti in survival rate. The F 1 progeny obtained from Ae. aegypti and Ae. albopictus treated at 39°C× 0.5ppm, 39°C× 1ppm did not show any significant difference in survival rate as compared to control. The survival rate is greatly reduced at 40°C× 1ppm, 40°C× 1.5ppm treatment. So, further study of F 1 progeny from larvae treated at these two respective doses were not carried out in the present study. Fecundity The mean total fecundity decreased significantly in both Ae. aegypti (F 2,12 =167.769 P = 0.000) and Ae. albopictus (F 2,12 =219.547, P = 0.000) derived from the thermally exposed larvae with the lowest fecundity observed at 40°C treated mosquito (Fig. 4 ). F 1 progeny obtained from thermally exposed larvae of both Ae. aegypti (F 2,12 =3.376, P = 0.069) and Ae. albopictus (F 2,12 =3.104, P = 0.82) did not show any difference in rate of fecundity. Like temperature exposed mosquito the mean total fecundity decreased significantly in Ae. aegypti (F 2,12 =1180.477, P ˂ 0.001) and Ae. albopictus (F 2,12 = 474.641, P ˂ 0.001) females derived from the Bti exposed larvae than control set. F 1 progeny obtained from Bti exposed larvae of both Ae. aegypti (F 2,12 = 1522.667, P ˂ 0.001) and Ae. albopictus (F 2,12 = 2194.667, P ˂ 0.001 ) show a significant difference in rate of fecundity. The fecundity of both Aedes mosquito significantly decreased when treated with 39°C× 1ppm, 39°C× 1.5 ppm, 40°C× 1ppm, 40°C× 1.5 ppm in a dose-dependent manner from the control group. A significant impact ( F1, 20 = 14.970, P = 0.001) of temperature and Bti interaction on rate of fecundity was noticed in Ae. albopictus but no such interaction was detected in Ae. aegypti . Fecundity of F 1 progeny did not differ significantly from control. Sex ratio The results indicate a significantly higher proportion of emergence of females in both Ae. aegypti (F 2,12 =100.667, P = 0.000) and Ae. albopictus (F 2,12 = 68.625, P = 0.000) exposed to temperature stress than in control set (Fig .3). The largest difference in sex ratio was noticed in the group of Ae. aegypti and Ae. albopictus which were exposed at 40°C. A significant increase in sex ratio was found between 39°C and 40°C treatment. The F 1 progeny obtained from Ae. aegypti and Ae. albopictus treated at 39°C× 0.5ppm, 39°C× 1ppm did not show any significant difference in sex ratio as compared to control set. The results indicate a significantly higher proportion of males in both Ae. aegypti (F 2,12 =70.679, P = 0.000 ) and Ae. albopictus (F 2,12 =144.440, P = 0.000 ) exposed to Bti. The largest difference in sex ratio was noticed in the group of Ae. aegypti and Ae. albopictus exposed to 1.5 ppm of Bti. The sex ratio did not differ among individuals exposed to different sublethal concentrations of Bti. It was noticed that Bti larvicide influenced the sex ratio while comparing the results of sublethal conc. with that of control. More female emerged in Ae. aegypti mosquito at 40°C× 1ppm, 40°C× 1.5ppm treatment in Ae. aegypti mosquito and no significant interaction was found between temperature and Bti (F 1,20 =3.866, P = .063). Whereas in Ae. albopictus the number of female increased at 39°C× 1.5ppm, 40°C× 1ppm, 40°C× 1.5ppm treatment and no significant interaction between temperature and Bti (F1,20 = 5.578, P = 0.058) was observed for this trait. The F 1 progeny of Ae. aegypti (F 2,12 =3.339, P = 0.070 ) and Ae. albopictus (F 2,12 =3.824, P = 0.052) exposed to 39°C× 0.5ppm, 39°C× 1ppm did not show any significant difference in sex ratio. Hatchability rate The proportion of larvae hatched from the eggs derived from both Ae. aegypti (F 2,12 =135.135, P = 0.000) and Ae. albopictus (F 2,12 =112.690, P = 0.000) exposed to temperature stress decreased significantly from control (Fig. 5 ). The F 1 progeny of Aedes mosquito treated with temperature at 39°C and 40°C did not show any significant difference in hatchability except in F 1 progeny of Ae. albopictus (F 2,12 =15.505, P = 0.001) treated at 40°C which showed a significant decrease in hatchability. The results also indicated that the hatchability of eggs was significantly decreased after Bti exposure in both Ae. aegypti (F 2,12 =244.556, P = 0.000 ) and Ae. albopictus (F 2,12 =54.319, P = 0.000) in dose dependent manner. Further, the hatchability of eggs was significantly decreased in the F 1 progeny of Bti exposed Ae. aegypti (F 2,12 =157.930, P ˂ 0.001) and Ae. albopictus (F 2,12 =117.875, P = ˂ 0.001). The hatchability significantly decreased in both Aedes at 39°C× 1.5ppm and significantly increased from control at 39°C× 1ppm treatment in Ae. albopictus . However, hatchability reduced nearly to zero in both Aedes treated at 40°C× 1ppm, 40°C× 1.5ppm respectively. The hatchability of F 1 progeny of both Aedes treated at 39°C× 1ppm and 39°C× 1.5 ppm did not differ significantly from control. Longevity Significant decrease in longevity of both Ae. aegypti (F 2,9 =8.485, P = 0.008 ) and Ae. albopictus (F 2,9 =23.661, P ˂0.001) was observed in mosquitoes exposed to temperature stress (40°C) (Fig. 6 ). F 1 progeny obtained from thermally exposed larvae of both Ae. aegypti and Ae. albopictus did not show any significant difference in the rate of longevity. Similarly the longevity decreased significantly in Ae. aegypti (F 2,9 =35.237, P = 0.008) and Ae. albopictus (F 2,9 =21.553, P ˂0.001) treated with Bti (1.0 and 1.5 ppm). F 1 progeny obtained from Bti exposed larvae of both Ae. aegypti and Ae. albopictus did not show any significant difference in the rate of longevity. The longevity increased in Ae. aegypti adult derived from larvae exposed to 39°C× 1ppm, 39°C× 1.5 ppm and decreased in adult derived from larvae exposed to 40°C× 1ppm, 40°C× 1.5 ppm. However, the longevity decreased in adult derived from larvae of Ae. albopictus in 39°C× 1ppm, 40°C× 1ppm, 40°C× 1.5 ppm and increased non significantly at 39°C× 1.5 ppm treatment respectively. F 1 progeny obtained from larvae of both Ae. aegypti and Ae. albopictus exposed to 39°C× 1ppm, 39°C× 1.5 ppm did not show any significant difference in rate of longevity. Discussion This study was undertaken to understand how the temperature stress and Bti influence life history traits of two important Aedes mosquito vectors Aedes aegypti and Aedes albopictus . Insects are ectotherms and environmental temperature greatly influences their survival, distribution, behavioral characteristics, life-history traits, and fitness (Cui et al., 2008 ; Denlinger and Yocum, 1998 ). When temperatures increase beyond an insect's optimal range, there are two conjointly exclusive consequences: survival or death (Denlinger and Yocum, 1998 ). Even a species could survive after exposure to temperature stress but fitness could be affected (Rinehart et al., 2000 ). Heat stress may cause the death of individuals by causing abnormalities at the cellular level due to changes in ion concentration and pH. Shortened development periods at higher temperatures reduce food supply and lead to death (Clements, 1992 ). Current results showed that both Aedes species exhibited different responses to thermal exposure. A reduction in developmental time was noticed after thermal stress in Aedes mosquito. The survival rate decreased after thermal exposure in both Aedes mosquito species. The number of eggs deposited by both species of Aedes mosquito was significantly decreased after thermal exposure. Earlier study by many researchers showed that thermal stress can affect ovarian development and cause damage to oocytes in females and reduce the fertility of male by injuring testes and sperm that could lead to a decrease in egg production (Chihrane and Lauge, 1994 ; 1997 ; Krebs and Loeschcke, 1994 ; Rinehart et al., 2000 ; Scott et al., 1997 ) which is similar to the current findings where hatchability was decreased in females obtained from thermally exposed larvae. More female emergence and lower longevity in thermally treated mosquito populations was noticed in the present study which is similar to the finding of Zhu et al., ( 2017 ) on Bradysia. The F 1 progeny derived from thermally exposed Aedes mosquito did not showed any significant difference in all life history traits. We didn’t observe any significant difference in developmental time of F 1 progeny derived from thermally exposed Aedes mosquito. The survival of F 1 progeny obtained from thermally exposed Aedes increased as compared to control. An increased fecundity and hatchability rate in progeny obtained from thermally exposed Ae. aegypti and Ae. albopictus was noticed in the present study from their parent. Sex ratio showed no significant difference in the F 1 progeny derived from thermally exposed Aedes mosquito from control. The incidence of dengue has grown dramatically in few decades worldwide. About half of the world's population is now at risk (WHO, 2020 ). So it is important to control its mosquito vector population. Further, the control of mosquito vector population during their immature stage is much easier as compared to adult stage as the movement of the larvae is restricted to its aquatic habitat. Sub-lethal effect is prolonging the developmental period of larvae which will support the chances of killing the larvae more in the aquatic habitat. In present study, Bti exposure did not show any significant difference from control in developmental period after exposure to Bti, which is similar to the findings of Flores et al., ( 2004 ). Mortality in larvae increased as the concentration of Bti increased which is in agreement with the results of Saleh and Wright ( 1989 ). In the present study, it was observed that the number of females was reduced with Bti treatments in exposed Aedes mosquito. It appears that immatures fated to be females are more prone to the Bti effect, indicating the effects of the toxin on larvae before pupation, resulting in ratios tilted towards males. So the use of Bti is advantageous because there would be a decrease in the reproductive population in the treated area which is similar to the findings of Flores et al., ( 2004 ) on Aedes aegypti . Saleh et al., ( 1990 ) on the contrary found more females than males in the treatment groups. Reproductive potential of Aedes mosquito was significantly reduced after Bti exposure which is similar to the findings of Saleh et al., ( 1990 ). A decrease in longevity of adults obtained from Bti exposed larvae were also found which was similar to the finding of Saleh et al., ( 1990 ). This may be because of a flagging action on the physiology of larvae and subsequently affecting the longevity of surviving adults. In present study, Bti exposure showed significant difference in developmental period of F 1 progeny from control which is similar to the findings of Flores et al., ( 2004 ). A decrease in the survival rate (although not significant) was found in F 1 progeny of Bti exposed Aedes observed with exception to F 1 derived from Ae. aegypti treated at 1.0 ppm Bti and F 1 derived from Ae. albopictus treated at 1.5 ppm of Bti. Reproductive potential of Aedes mosquito was significantly reduced in F 1 progeny derived from Bti exposed parent. This is contrary to the findings of Saleh et al., ( 1990 ) where Bti treatment reduces the reproductive potential of Culex pipiens in the first generation (treated) but remain unchanged in their progeny. The developmental period showed non-significant difference in larvae exposed to 39°C× 0.5ppm, 39°C× 1ppm, 40°C× 0.5ppm, 40°C× 1ppm. However, a significant decrease in survival rate was noticed in both Aedes mosquito after all treatments such as 39°C× 1ppm, 39°C× 1.5 ppm, with high reduction at 40°C× 1ppm and 40°C× 1.5ppm. More female emergence was observed in Ae. aegypti mosquito in 40°C× 1ppm, 40°C× 1.5ppm treatment and in Ae. albopictus , the number of female increases at 39°C× 1.5ppm, 40°C× 1ppm, 40°C× 1.5ppm treatment. The fecundity of both Aedes mosquito significantly decreased when treated with at 39°C× 1ppm, 39°C× 1.5 ppm, 40°C× 1ppm, 40°C× 1.5 ppm in a dose-dependent manner. The hatchability significantly decreased in both Aedes at 39°C× 1.5ppm and significantly increased from control at 39°C× 1ppm treatment. However, hatchability reduced nearly to zero in both Aedes mosquito treated at 40°C× 1ppm, 40°C× 1.5ppm. The longevity increased in Ae. aegypti adult derived from larvae exposed to 39°C× 1ppm, 39°C× 1.5 ppm and decreased in larvae exposed to 40°C× 1ppm, 40°C× 1.5 ppm. However, the longevity decreased in adult derived from larvae of Ae. albopictus in 39°C× 1ppm, 40°C× 1ppm, 40°C× 1.5 ppm and increased non significantly at 39°C× 1.5 ppm treatment. The developmental period of F 1 progeny derived from mosquito treated at 39°C× 1ppm, 39°C× 1.5ppm showed a significant difference in any life history traits. Conclusion In the present study, it has been observed that temperature and Bti significantly influence the behavioral traits in Aedes mosquito. Temperature stress imparts negative influence on Aedes mosquito by decreasing survival, longevity and reproductive potential while it imparts some positive effects like decreasing developmental period and producing more female offspring which can increase mosquito population and transmission of pathogens (as female mosquito carry pathogen). Similarly, Bti alone affects most of the life history traits beyond the parental generation. However, temperature stress alone and the combined effect (or interaction) of both stress do not affect the life history traits significantly in F 1 generation. Bti exposure increased the developmental period, reduced reproductive potential of the Aedes mosquito in F 1 generation. Therefore, it may be concluded that Bti can be used as an effective tool for Aedes mosquito vector control. Temperature and Bti in combination reduce survival rate and reproductive potential in Aedes mosquito. Consequently, it appears that while global warming may cause an increase in dengue transmission, based on the current findings, Bti can be used for dengue prevention and control in the current climatic condition. Abbreviations Not applicable Declarations Ethics approval and consent to participate Not applicable. Consent for publication Not applicable. Availability of data and materials Data generated during this study are included in this published article Competing interests The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Funding This study had no funding. Authors’ contributions TSA executed the experiment and carried out data analysis and manuscript writing, TKB designed the experiment, carried out data analysis. Both the authors have read and approved the manuscript. Acknowledgements We would like to thank to the head, Post Graduate Department of Zoology, Berhampur University, Berhampur, Odisha, for providing necessary facilities and encouragement. Author details 1 Post-Graduate Department of Zoology, Berhampur University, Berhampur-760007, Odisha, India. References Achari, T.S., Acharya, U.R., Barik, T.K. (2017). Impact of thermal stress on survival and induced cross-tolerance to toxins of Bacillus thuringiensis in wild Aedes aegypti . International Journal of Bioscience, 11,156–164. https://doi.org/10.12692/ijb/11.1.156-164 . Achari, T.S., Barik, T.K. (2019). Assessment of Temperature-induced Cross-tolerance to Bacillus thuringiensis subsp. israelensis on Field-collected Aedes albopictus . Biopestice International, 15, 97–104. Alto, B.W., Bettinardi, D. (2013). Temperature and dengue virus infection in mosquitoes: independent effects on the immature and adult stages. American Journal of Tropical Medicine and Hygiene, 88(3), 497–505. https://doi.org/10.4269/ajtmh.12-0421 Briegel, H., Knusel, I., Timmermann, S.E. (2001). Aedes aegypti : size, reserves, survival, and flight potential. Journal of Vector Ecology, 26(1), 21–31. Briegel, H., Timmermann, S.E. (2001). Aedes albopictus (Diptera: Culicidae): physiological aspects of development and reproduction. Journal of Medical Entomology, 38(4), 566–571. Briegel, H., Waltert, A., Kuhn, R. (2000). Reproductive physiology of Aedes (Aedimorphus) vexans (Diptera: Culicidae) in relation to flight potential. Journal of Medical Entomology, 38(4), 557–565. https://doi.org/10.1603/0022-2585-38.4.557 Chihrane, J., Lauge, G. (1994). Effects of high-temperature shocks on male germinal cells of Trichogramma brassicae (Hymenoptera, Trichogrammatidae). Entomophaga, 39(1), 11–20. Chihrane, J., Lauge, G. (1997). Thermosensitivity of germ lines of Trichogramma brassicae Bezdenko (Hymenoptera) - implications for efficacy of the parasitoid. Canadian Journal of Zoology, 75, 484–489. Clements, A.N. (1992). The biology of mosquitoes: Development, nutrition and reproduction, p.150–170. In A.N. Cui, X., Wan, F., Xie, M., and Liu, T. (2008). Effects of Heat Shock on Survival and Reproduction of Two Whitefly Species, Trialeurodes vaporariorum and Bemisia tabaci Biotype B. Journal of Insect Science, 8(24),1–10. Denlinger, D.L., Yocum, G.D. (1998). Physiology of heat sensitivity. In: Hallman GJ, Denlinger DL, editors. Thermal sensitivity in insects and application in integrated pest management 11–18. Westview Press, Boulder, Colorado, USA. Dixit, V., Gupta, A.K., Kataria, O., Prasad, G.B.K.S. (2002). Population dynamics of Culex quinquefasciatus filaria vector in Raipur City of Chhattisgarh State. Journal of Communicable Diseases, 34(3), 193–202. Flipse, J. and Smit, J.M. (2015). The Complexity of a Dengue Vaccine: A Review of the Human Antibody Response. PLOS Neglected Tropical Diseases, 9(6), e0003749. Flores, A.E., Garcia, G.P., Badii, M.H., Rodriguez Tovar, M.A., Fernandez Salas, I. (2004). Effects of sublethal concentrations of Vectobac on biological parameters of Aedes aegypti . Journal of the American Mosquito Control Association, 20(4), 412–417. Glunt, K.D., Blanford, J.I., Paaijmans, K.P. (2013). Chemicals, climate, and control: increasing the effectiveness of malaria vector control tools by considering relevant temperatures. PLOS Pathogens , 9 (10), p. e1003602, 10.1371/journal.-ppat.1003602 Gray, K.M., Burkett-Cadena, N.D., Eubanks, MD, Unnasch TR (2011). Crepuscular flight activity of Culex erraticus (Diptera: Culicidae). Journal of Medical Entomology, 48(2), 167–172. https://doi.org/10.1603/me10176 Helinski, M.E.H., Parker, A.G., Knols, B.G.J. (2009). Radiation biology of mosquitoes. Malaria Journal, 8(Suppl. 2), S6. https://doi.org/10.1186/1475-2875-8-S2-S6 Krebs, R.A., Loeschcke, V. (1994). Effects of exposure to short-term heat stress on fitness components in Drosophila melanogaster . Journal of Evolutionary Biology, 7(1), 39–49. https://doi.org/10.1046/j.1420-9101.1994.7010039.x Lacey, L.A. (2007). Bacillus thuringiensis serovariety israelensis and Bacillus sphaericus for mosquito control. Journal of the American Mosquito Control, 23(2), 133–163. https://doi.org/10.2987/8756-971x (2007)23[133:btsiab]2.0.co;2 Meyer, R.P., Hardy, J.L., Reisen, W.K. (1990). Diel changes in adult mosquito microhabitat temperatures and their relationship to the extrinsic incubation of arbovirues in mosquitoes in Kern County, California. Journal of Medical Entomology, 27(4), 607–614. https://doi.org/10.1093/jmedent/27.4.607 Rinehart, J.P., Yocum, G.D., Denlinger, D.L. (2000). Thermotolerance and rapid cold hardening ameliorate the negative effects of brief exposures to high or low temperatures on fecundity in the flesh fly, Sarcophaga crassipalpis . Physiological Entomology, 25(4), 330–336. https://doi.org/10.1111/j.1365-3032.2000.00201.x Rohr, J.R., Schotthoefer, A.M., Raffel, T.R., Carrick, H.J., Halstead, N., Hoverman, J.T., Johnson, C.M., Johnson, L.B., Lieske, C., Piwoni, M.D., Schoff, P.K. and Beasley, V.R. (2008). Agrochemicals increase trematode infections in a declining amphibian species. Nature 455, 1235–1239. https://doi.org/10.1038/nature07281 Rowley, W.A., Graham, C.L. (1968). The effect of temperature and relative humidity on the flight performance of female Aedes aegypti . Journal of Insect Physiology, 14(9), 1251–1257. https://doi.org/10.1016/0022-1910(68)90018-8 Saleh, M.S., Kelada, N.L., and Abdeen, M.I. (1990). The delayed effects of Bacillus thuringiensis H-14 on the reproductive potential and subsequent larval development of the mosquito Culex pipiens L. Journal of Applied Entomology, 109(1–5), 520–523. Saleh, M.S., Wright, R.E. (1989). Effects of the IGR cyromazine and the pathogen Bacillus thuringiensis var. israelensis on the mosquito Aedes epucticus . Journal of Applied Entomology, 108(4), 381–385. http://dx.doi.org/10.1111/j.1439-0418.1989.tb00471.x Sandland, G.J., and Carmosini, N. (2006). Combined effects of a herbicide (atrazine) and predation on the life history of a pond snail, Physa gyrina. Environmental Toxicology and Chemistry, 25(8), 2216–2220. https://doi.org/10.1897/05-596R.1 Scott, M., Berrigan, D., Hoffmann, A.A. (1997). Costs and benefits of acclimation to elevated temperature in Trichogramma carverae . Entomologia Experimentalis et Applicata, 85(3), 211–219. https://doi.org/10.1046/j.1570-7458.1997.00251.x Swain, V., Seth, R.K., Mohanty, S.S., Raghavendra, K. (2008). Effect of temperature on development, eclosion, longevity and survivorship of malathion-resistant and malathion-susceptible strain of Culex quinquefasciatus . Parasitology Research, 103(2), 299–303. https://doi.org/10.1007/s00436-008-0969-5 Weis, J.S., Smith, G., Zhou, T., Santiago-Bass, C., and Weis, P. (2001). Effects of contaminants on behavior: Biochemical mechanisms and ecological consequences. Bioscience, 51(3), 209–217. https://doi.org/10.1641/0006-3568(2001)051[0209:EOCOBB]2.0.CO;2 WHO (1988). Environmental Management for Vector Control. Training and informational materials slides set series. World health organization . http://helid.digicollection.org/en/d/Jwhow01e/ . Accessed on 18.6.2021 WHO (2006). Guidelines for testing mosquito adulticides for indoor residual spraying and treatment of mosquito nets. https://apps.who.int/iris/handle/10665/69296 . Accessed on 18.6.2021 WHO (2020). Vector borne disease factsheet. https://www.who.int/news-room/fact-sheets/detail/vector-borne-diseases . Accessed on 2.3.2020 Wright, R.E. and Knight, K.L. (1966). Effect of environmental factors on biting activity of Aedes vexans (Meigen) and Aedes trivittatus (Coquillett). Mosquito News, 26(4), 565–578. Zhu, G., Xue, M., Luo, Y., Ji, G., Liu, F., Zhao, H. and Sun, X. (2017). Effects of short-term heat shock and physiological responses to heat stress in two Bradysia adults, Bradysia odoriphaga and Bradysia difformis . Scientific Reports, 7, 13381. https://doi.org/10.1038/s41598-017-13560-4 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6635876","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":513821585,"identity":"db7132bc-d4be-4fc2-8695-40015bda9032","order_by":0,"name":"T. 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F\u003c/strong\u003e\u003csub\u003e\u003cstrong\u003e1\u003c/strong\u003e\u003c/sub\u003e\u003cstrong\u003e progeny (untreated) were derived from treated parent populations. Different upper-case letters indicate significant differences among treatment in each species (Tukey’s HSD, P \u0026lt; 0.05). Number of * indicates level of significance.\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-6635876/v1/28e7938fd543937a7041872a.png"},{"id":91466621,"identity":"9f183412-18ce-4eb2-82da-77ad7730fc94","added_by":"auto","created_at":"2025-09-16 18:51:45","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":75564,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003ePercentage survival (Mean ± SE) of \u003c/strong\u003e\u003cem\u003e\u003cstrong\u003eAe. aegypti \u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003eand \u003c/strong\u003e\u003cem\u003e\u003cstrong\u003eAe. albopictus \u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003eafter (a) Temperature, (b) Bti, (c)\u0026nbsp; Temperature × Bti exposure. F\u003c/strong\u003e\u003csub\u003e\u003cstrong\u003e1\u003c/strong\u003e\u003c/sub\u003e\u003cstrong\u003e progeny (untreated) were derived from treated parent populations. Different upper-case letters indicate significant differences among treatment in each species (Tukey’s HSD, P \u0026lt; 0.05). Number of * indicates level of significance.\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-6635876/v1/d8c7b74391453004f6948408.png"},{"id":91466220,"identity":"d255add9-0db2-4a13-b8ba-026cf2812ae0","added_by":"auto","created_at":"2025-09-16 18:43:45","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":81358,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eFecundity (Mean ± SE) of \u003c/strong\u003e\u003cem\u003e\u003cstrong\u003eAe. aegypti \u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003eand \u003c/strong\u003e\u003cem\u003e\u003cstrong\u003eAe. albopictus \u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003eafter (a) Temperature, (b) Bti, (c)\u0026nbsp; Temperature × Bti exposure. F\u003c/strong\u003e\u003csub\u003e\u003cstrong\u003e1\u003c/strong\u003e\u003c/sub\u003e\u003cstrong\u003e progeny (untreated) were derived from treated parent populations. Different upper-case letters indicate significant differences among treatment in each species (Tukey’s HSD, P \u0026lt; 0.05). Number of * indicates level of significance.\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-6635876/v1/eaab3b83bec4783fb88d013b.png"},{"id":91467309,"identity":"9af1f45c-d3e9-4d78-a907-63faa8ae0ba4","added_by":"auto","created_at":"2025-09-16 18:59:45","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":78038,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eSex ratio (Mean ± SE) of \u003c/strong\u003e\u003cem\u003e\u003cstrong\u003eAe. aegypti \u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003eand \u003c/strong\u003e\u003cem\u003e\u003cstrong\u003eAe. albopictus \u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003eafter (a) Temperature, (b) Bti, (c)\u0026nbsp; Temperature × Bti exposure. F\u003c/strong\u003e\u003csub\u003e\u003cstrong\u003e1\u003c/strong\u003e\u003c/sub\u003e\u003cstrong\u003e progeny (untreated) were derived from treated parent populations. Different upper-case letters indicate significant differences among treatment in each species (Tukey’s HSD, P \u0026lt; 0.05). Number of * indicates level of significance.\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-6635876/v1/9959722db4583439cce097e7.png"},{"id":91467618,"identity":"804f18a8-06ae-4767-a704-29d1de398d80","added_by":"auto","created_at":"2025-09-16 19:07:45","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":72803,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eHatchability (Mean ± SE) of \u003c/strong\u003e\u003cem\u003e\u003cstrong\u003eAe. aegypti \u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003eand \u003c/strong\u003e\u003cem\u003e\u003cstrong\u003eAe. albopictus \u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003eafter (a) Temperature, (b) Bti, (c)\u0026nbsp; Temperature × Bti exposure. F\u003c/strong\u003e\u003csub\u003e\u003cstrong\u003e1\u003c/strong\u003e\u003c/sub\u003e\u003cstrong\u003e progeny (untreated) were derived from treated parent populations. Different upper-case letters indicate significant differences among treatment in each species (Tukey’s HSD, P \u0026lt; 0.05). Number of * indicates level of significance.\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-6635876/v1/81770f10a3bd68d0f6127c8a.png"},{"id":91467621,"identity":"f8fa777f-d3ac-4767-bf6a-5ad8397db178","added_by":"auto","created_at":"2025-09-16 19:07:45","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":75438,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eLongevity (Mean ± SE) of \u003c/strong\u003e\u003cem\u003e\u003cstrong\u003eAe. aegypti \u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003eand \u003c/strong\u003e\u003cem\u003e\u003cstrong\u003eAe. albopictus \u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003eafter (a) Temperature, (b) Bti, (c)\u0026nbsp; Temperature × Bti exposure. F\u003c/strong\u003e\u003csub\u003e\u003cstrong\u003e1\u003c/strong\u003e\u003c/sub\u003e\u003cstrong\u003e progeny (untreated) were derived from treated parent populations. Different upper-case letters indicate significant differences among treatment in each species (Tukey’s HSD, P \u0026lt; 0.05). Number of * indicates level of significance.\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e","description":"","filename":"6.png","url":"https://assets-eu.researchsquare.com/files/rs-6635876/v1/b7888f16e88c79ae3f7580b9.png"},{"id":91818473,"identity":"eae9ed2b-d2bd-4cf2-b9e9-c05e5f9cb851","added_by":"auto","created_at":"2025-09-22 07:04:34","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2053729,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6635876/v1/fe1d2d85-ae1e-4949-a581-a4fe7b3d35cf.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Effects of temperature and Bacillus thuringiensis israelensis on life history traits of Aedes aegypti and Aedes albopictus mosquito species","fulltext":[{"header":"Background","content":"\u003cp\u003eClimatic changes forecasted in the coming years are likely to result in substantial alterations to the distributions and populations of vectors of arthropod-borne pathogens. The Intergovernmental Panel on Climate Change has predicted 2\u0026ndash;4\u0026deg;C rise in mean global temperature over the next century (IPCC 2007) that result in significant changes to ecological landscapes and patterns of infectious disease. In tropical and subtropical countries, people are at risk of infection from many mosquito vector-borne diseases. \u003cem\u003eAedes\u003c/em\u003e mosquito, the vector of dengue and chikungunya is very resistant to different control tactics as it is closely associated with domestic and peridomestic human settings (Reiter \u0026amp; Gubler, 1997). Efficient and commercially viable vaccines are not yet available for these vector-borne diseases. Therefore, the prevention and control of such vector-borne diseases remain dependent on different strategies which include the use of different chemical insecticides to minimize the risk of transmission. Thus, the mosquito control programs unsurprisingly swing towards the use of microbial, phytochemicals and other biocontrol strategies (Lacey, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2007\u003c/span\u003e). \u003cem\u003eBacillus thuringiensis\u003c/em\u003e subsp. \u003cem\u003eisraelensis\u003c/em\u003e (Bti) and its derivatives represent a safe and eco-friendly alternative to chemical insecticides for the management of mosquito vector.\u003c/p\u003e\u003cp\u003eMany biotic and abiotic environmental factors affect different life stages of mosquito. As mosquitoes occupy holometabolous life, different environmental niches during their immature as well as mature stages are influenced by environmental conditions. The larval stages of mosquitoes are stages that confined to aquatic habitats. The availability of containers in nature determines the micro climatic condition by the larval stages of \u003cem\u003eAedes\u003c/em\u003e mosquito (Alto and Bettinardi, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2013\u003c/span\u003e). However, the adult stage is highly mobile and daily environmental temperature influenced mosquito activity (Gray et al., \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2011\u003c/span\u003e; Meyer et al., \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e1990\u003c/span\u003e; Rowley and Graham, \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e1968\u003c/span\u003e; Wright and Knight, 1996). Therefore, change in environmental temperature between two different stages of mosquito such as immature and mature is a common phenomenon in nature. The environmental conditions faced during the development especially the early stages may have strong downstream effects on the life history traits. Further, environmental temperature also influence the immature stages of mosquito to develop the adult phenotype e.g., nutritional reserves (Briegel et al., \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2000\u003c/span\u003e; Briegel and Timmermann, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2001\u003c/span\u003e; Briegel et al., \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2001\u003c/span\u003e) and may also modify lifespan and susceptibility of adults to the pathogen.\u003c/p\u003e\u003cp\u003eMosquito life history traits, pathogen transmission, vectorial capacity are highly influenced by different environmental conditions, therefore, a better understanding of their response to different environmental conditions especially temperature can lead to more accurate forecasts of disease transmission and the development of new, novel, effective control strategies.\u003c/p\u003e\u003cp\u003eMosquito larvae are exposed to insecticides in the presence of many environmental stressors. Standard toxicological studies are usually piloted in the absence of these environmental stressors which is expected to underestimate the lethal effects of insecticides on mosquitoes. However, insecticide toxicity depends on the type of formulation, insect biology, and the environment in which these interact. Thus, it is difficult to predict how an insecticide susceptibility test in a controlled laboratory condition decodes to the efficacy of an insecticide in the field condition (Glunt et al., \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2013\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eGenerally, laboratory based experiments give some indication on the effect of temperature by maintaining insects either at different constant temperatures or on different fixed temperature cycles. In nature, ectothermic creatures may experience extreme temperature for a few hours that may cause changes in body temperatures for a very short duration and also induce residual effects that continue even after the temperature returns to its normal condition. Similarly, insecticide is another important factor that may influence the behavioral characteristics and viability of mosquitoes. \u003cem\u003eAedes aegypti\u003c/em\u003e and \u003cem\u003eAe. albopictus\u003c/em\u003e population experience variations in various concentrations of insecticide, which may cause changes in their growth, behavior and development. The influence of a particular insecticide on immature stages of mosquito basically depends on the dose, intensity and duration of exposure of insecticide. High dose of insecticide have a severe impact that kills insects population while low insecticide concentrations in sublethal doses can change in morphological, behavioural, immune, hormonal, and reproductive functions (Rohr et al., \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2008\u003c/span\u003e; Sandland and Carmosini, \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2006\u003c/span\u003e; Weis et al., \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2001\u003c/span\u003e). So, it is important to know the effect of insecticide and temperature individually or in combination on behavioral traits of mosquito not only in exposed population but beyond it in the next generation or in several generations for developing a better control strategy. It is very important to investigate such effects in local strain in response to climate variation.\u003c/p\u003e\u003cp\u003eMosquito populations are most widespread in tropical areas with average temperatures ranging from 25\u0026deg;C to 35\u0026deg;C (Dixit et al., \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2002\u003c/span\u003e), but they still survive in low density in different habitats with such extreme conditions. In India, although for a short duration the average daytime environmental temperature during the summer exceeds 40\u0026deg;C hence, it is critical for larvae occupying habitats exposed to such high environmental temperature (Swain et al., \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2008\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eTherefore, in the present study, experiments were conducted to understand how thermal stress and Bti insecticide affect certain behavioral traits of two important mosquito vectors \u003cem\u003eAe. aegypti\u003c/em\u003e and \u003cem\u003eAe. albopictus\u003c/em\u003e. Specifically, investigation were made to understand the effect of thermal stress and Bti on development time, survivability, fecundity, hatchability, sex ratio and longevity of \u003cem\u003eAe. aegypti\u003c/em\u003e and \u003cem\u003eAe. albopictus\u003c/em\u003e. The LT\u003csub\u003e50\u003c/sub\u003e value at 40\u0026deg;C was 62.03 min and 62.05 min for \u003cem\u003eAe. aegypti\u003c/em\u003e and \u003cem\u003eAe. albopictus\u003c/em\u003e respectively and both larvae survived up to 300 minutes exposure at 39\u0026deg;C. The LC\u003csub\u003e50\u003c/sub\u003e and LC\u003csub\u003e90\u003c/sub\u003e value for Bti was 0.931 ppm and 2.23 ppm in \u003cem\u003eAe. aegypti\u003c/em\u003e and 0.835 ppm and 1.968 ppm in \u003cem\u003eAe. albopictus\u003c/em\u003e respectively (Achari et al., \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2017\u003c/span\u003e; 2019). Two temperatures doses (39\u0026deg;C and 40\u0026deg;C) for sublethal period and two Bti concentrations (1 ppm and 1.5 ppm) were taken in the present study.\u003c/p\u003e"},{"header":"Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003eMosquito and standard rearing conditions\u003c/h2\u003e\u003cp\u003e\u003cem\u003eAedes aegypti\u003c/em\u003e and \u003cem\u003eAe. albopictus\u003c/em\u003e mosquito were originally collected from different parts of berhampur city (19\u0026deg; 18' 53.8632'' N and 84\u0026deg; 47' 38.7240'' E.) Ganjam District of Odisha State, India and maintained at 25\u0026thinsp;\u0026plusmn;\u0026thinsp;1\u0026deg;C and relative humidity of 65\u0026thinsp;\u0026plusmn;\u0026thinsp;5% with 12 hour light and dark photoperiods in an insectary. Larvae were fed with a mixture of yeast powder and dog biscuits in the ratio of 3:2 (Helinski et al., \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2009\u003c/span\u003e). Adults had continuous access to food of 10% glucose solution and raisins soaked in water. Females were blood-fed using artificial blood-feeders, as needed. Late third instar larvae of field-collected \u003cem\u003eAedes\u003c/em\u003e mosquitoes were used to conduct this experiment.\u003c/p\u003e\u003c/div\u003e\n\u003ch3\u003eThermal stress assay\u003c/h3\u003e\n\u003cp\u003eLate third instar larvae of \u003cem\u003eAe. aegypti\u003c/em\u003e and \u003cem\u003eAe. albopictus\u003c/em\u003e (25 individuals/replicate) were placed in 250 ml of tap water separately and maintained in a thermostatically regulated water bath to observe the effect of temperature as per the guidelines of WHO (\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e1988\u003c/span\u003e, \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e2006\u003c/span\u003e) at 10 min intervals. This experiment was replicated a minimum of 5 times. Larvae at 25\u0026thinsp;\u0026plusmn;\u0026thinsp;l\u0026deg;C were used as control whereas 39\u0026deg;C and 40\u0026deg;C for a sub-lethal period were used as experimental temperature with the standard photoperiod. The selection of this temperature range was based on a simple algorithm as below and above 40\u0026deg;C which is recognized as the threshold temperature for survival of immature stage and later development (Bayoh and Lindsay, 2004). The temperature of the water having mosquito larvae in water bath was increased slowly in such a way that the temperature will increase by 2\u0026deg;C in 20 min. Live \u003cem\u003eAedes\u003c/em\u003e mosquito larvae were taken for life history study after temperature exposure.\u003c/p\u003e\n\u003ch3\u003eBti bioassay\u003c/h3\u003e\n\u003cp\u003eCommercially available Bti was procured from Summit Chemical, Baltimore, USA for evaluation against \u003cem\u003eAe. aegypti\u003c/em\u003e and \u003cem\u003eAe. albopictus\u003c/em\u003e. Late third instar larvae were treated with different concentrations of Bti ranging from 0.5\u0026ndash;2.5 ppm as per the guidelines of WHO (\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e1988\u003c/span\u003e, \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e2006\u003c/span\u003e). Minimum of five replicates of 25 larvae each were taken for Bti treatment. For the life history study, Bti doses between LC\u003csub\u003e50\u003c/sub\u003e and LC\u003csub\u003e70\u003c/sub\u003e (1 ppm and 1.5 ppm) were taken as fewer larvae survived above this dose and thus difficult to execute further study.\u003c/p\u003e\u003cp\u003e\u003cb\u003eBti exposure to thermally adapted\u003c/b\u003e \u003cb\u003eAedes\u003c/b\u003e \u003cb\u003elarvae\u003c/b\u003e\u003c/p\u003e\u003cp\u003eLarvae of \u003cem\u003eAedes\u003c/em\u003e mosquitoes were exposed at 39\u0026deg;C and 40\u0026deg;C for sublethal period (240 min and 60 min for 39\u0026deg;C and 40\u0026deg;C respectively) and were re-exposed to \u003cem\u003eBti\u003c/em\u003e solution of 1.0 ppm and 1.5 ppm. After 24 h recovery, viable mosquito larvae were taken randomly for life history assay. All life history traits such as development time, survivability, sex ratio, fecundity, hatchability and longevity were assessed in treated parent generation and its F\u003csub\u003e1\u003c/sub\u003e generation (untreated).\u003c/p\u003e\u003cp\u003e\u003cb\u003eAssessment of life history traits\u003c/b\u003e \u003cb\u003eAedes\u003c/b\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003eLarval developmental period\u003c/b\u003e - Developmental time in terms of development from first instar larvae to emergence of adults were assessed after treatment to the early fourth instar larva.\u003c/p\u003e\u003cp\u003e\u003cb\u003eSurvivability rate-\u003c/b\u003e Survivability rate was assessed by following larval development from first instar larvae to emergence of adults.\u003c/p\u003e\u003cp\u003e\u003cb\u003eAdult sex-ratio -\u003c/b\u003e After adult emergence from treated larvae through pupae, females and males were calculated, and the sex ratio (female/ male proportion) was determined. Adults were left for mating in adult cages and used for fecundity and hatchability studies.\u003c/p\u003e\u003cp\u003e\u003cb\u003eFecundity-\u003c/b\u003e The fecundity experiments were conducted by taking an equal number of male and female mosquito larvae that had emerged from the control and treated sets. These were placed in individual 30\u0026times;30 cm cages for each concentration. Three days after the blood meal, eggs were collected daily from small plastic bowls containing water kept in an ovitrap in the cages. Fecundity was calculated from the number of eggs laid in ovitraps divided by the number of mated females. Death of adults in these experiments was taken into account\u003c/p\u003e\u003cp\u003e\u003cb\u003eHatchability -\u003c/b\u003e Hatchability was measured in percentage as the number of hatched eggs by the total number of collected eggs after treatment to the early fourth instar larva.\u003c/p\u003e\u003cp\u003e\u003cb\u003eLongevity-\u003c/b\u003e The adult longevity of male and female mosquitoes (F1 generation) was also recorded. This was calculated as the number of days lived by the adult. Total number of days from adult emergence to death was recorded and the means were calculated to give the mean longevity in days.\u003c/p\u003e\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e\u003ch2\u003eStatistical analysis\u003c/h2\u003e\u003cp\u003eProbit regression analysis which the slope, LC50, LC70, LC90 and their 95% confidential intervals (CI) were obtained. The toxicity (ITU/mg) of the Bti product was determined according to the following formula:\u003c/p\u003e\u003cp\u003ePotency (Bti product)\u0026thinsp;=\u0026thinsp;LC50 (standard)/ LC50 (Bti product) x potency (standard)\u003c/p\u003e\u003cp\u003eObtained data were analyzed using a one-way analysis of variance (ANOVA) and Two-way analysis to find out interaction between temperature and Bti in life history trait followed by multiple comparisons with Tukey\u0026rsquo;s HSD to identify statistically significant differences between the treated and untreated (control) group.\u003c/p\u003e\u003c/div\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\u003ch2\u003eDevelopment time\u003c/h2\u003e\u003cp\u003eA significant decrease in developmental period in both \u003cem\u003eAedes\u003c/em\u003e mosquito was observed after exposure to 39\u0026deg;C and 40\u0026deg;C respectively. Decrease in development time of 1.6 and 2 days in \u003cem\u003eAe. aegypti\u003c/em\u003e (F\u003csub\u003e2,12\u003c/sub\u003e= 21.00, P ˂ 0.001) and 1.6 and 1.8 day in \u003cem\u003eAe. albopictus\u003c/em\u003e was observed in comparison to control (F\u003csub\u003e2,12\u003c/sub\u003e= 25.750, P\u0026thinsp;=\u0026thinsp;0.001). However, there was no such significant difference noticed in developmental time in F\u003csub\u003e1\u003c/sub\u003e progeny of thermally exposed \u003cem\u003eAe. aegypti\u003c/em\u003e (F2,12\u0026thinsp;=\u0026thinsp;0.783, P\u0026thinsp;=\u0026thinsp;0.479 ) and \u003cem\u003eAe. albopictus\u003c/em\u003e (F\u003csub\u003e2,12\u003c/sub\u003e=1.130, P\u0026thinsp;=\u0026thinsp;0.355 ) (Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eMean developmental period of \u003cem\u003eAe. aegypti\u003c/em\u003e and \u003cem\u003eAe. albopictus\u003c/em\u003e, surviving from larvae exposed to sublethal concentrations (1 ppm and 1.5ppm) of Bti larvicide indicates a non-significant difference (P ˃ 0.05) as compared to control. The developmental period increased non-significantly with an increase in Bti conc. An analysis of the mean developmental time of F\u003csub\u003e1\u003c/sub\u003e of \u003cem\u003eAe. aegypti\u003c/em\u003e (F\u003csub\u003e2,12\u003c/sub\u003e=28.778, P ˂ 0.001 ) and \u003cem\u003eAe. albopictus\u003c/em\u003e (F\u003csub\u003e2,12\u003c/sub\u003e=25.333, P ˂ 0.001), exposed with sublethal concentrations of 1 and 1.5 ppm of Bti indicates a significant increase as compared to control.\u003c/p\u003e\u003cp\u003eTwo way ANOVA analysis showed the developmental period increased non-significantly in larvae exposed to 39\u0026deg;C\u0026times;0.5ppm, 39\u0026deg;C\u0026times; 1ppm, 40\u0026deg;C\u0026times; 0.5ppm, 40\u0026deg;C\u0026times;1ppm from control group in \u003cem\u003eAe. aegypti\u003c/em\u003e (F\u003csub\u003e1,20\u003c/sub\u003e= 0.035, P\u0026thinsp;=\u0026thinsp;0.853) and \u003cem\u003eAe. albopictus\u003c/em\u003e (F\u003csub\u003e1,20\u003c/sub\u003e= 1.225, P\u0026thinsp;=\u0026thinsp;0.282). However, we observed that developmental period did not differ significantly in F\u003csub\u003e1\u003c/sub\u003e progeny derived from \u003cem\u003eAe. aegypti\u003c/em\u003e (F\u003csub\u003e2,12\u003c/sub\u003e= 1.385, P\u0026thinsp;=\u0026thinsp;0.288) and \u003cem\u003eAe. albopictus\u003c/em\u003e (F\u003csub\u003e2,12\u003c/sub\u003e=1.103, P\u0026thinsp;=\u0026thinsp;0.363) treated at 39\u0026deg;C\u0026times; 1ppm, 39\u0026deg;C\u0026times; 1.5ppm respectively.\u003c/p\u003e\u003c/div\u003e\n\u003ch3\u003eSurvival rate\u003c/h3\u003e\n\u003cp\u003eSurvival of \u003cem\u003eAe. aegypti\u003c/em\u003e (F\u003csub\u003e2,12\u003c/sub\u003e= 27.320, P\u0026thinsp;=\u0026thinsp;0.000) and \u003cem\u003eAe. albopictus\u003c/em\u003e (F\u003csub\u003e2,12\u003c/sub\u003e= 23.326, P\u0026thinsp;=\u0026thinsp;0.000) decreased significantly to 1 and 1.7 fold at 40\u0026deg;C treatment with respect to control set. A non-significant decrease in survival rate was observed after exposure to 39\u0026deg;C in both \u003cem\u003eAedes\u003c/em\u003e mosquitoes. F\u003csub\u003e1\u003c/sub\u003e progeny obtained from thermally exposed larvae of \u003cem\u003eAe. aegypti\u003c/em\u003e (F\u003csub\u003e2,12\u003c/sub\u003e=2.540, P\u0026thinsp;=\u0026thinsp;0.120) and \u003cem\u003eAe. albopictus\u003c/em\u003e (F\u003csub\u003e2,12\u003c/sub\u003e=3.450, P\u0026thinsp;=\u0026thinsp;0.066) showed no such significant difference in survival rate (Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eSignificant decrease in the survival rate in \u003cem\u003eAe. aegypti\u003c/em\u003e (F\u003csub\u003e2,12\u003c/sub\u003e= 17.055, P\u0026thinsp;=\u0026thinsp;0.000) and \u003cem\u003eAe. albopictus\u003c/em\u003e (F\u003csub\u003e2,12\u003c/sub\u003e=31.317, P\u0026thinsp;=\u0026thinsp;0.000) was observed after exposure to Bti with lower survival at 1.5 ppm of Bti in both \u003cem\u003eAedes\u003c/em\u003e mosquito. A nonsignificant decrease in the survival rate was found in F\u003csub\u003e1\u003c/sub\u003e progeny of Bti exposed \u003cem\u003eAe. aegypti\u003c/em\u003e (F\u003csub\u003e2,12\u003c/sub\u003e=1.896, P\u0026thinsp;=\u0026thinsp;0.193) and \u003cem\u003eAe. albopictus\u003c/em\u003e (F\u003csub\u003e2,12\u003c/sub\u003e=2.733, P\u0026thinsp;=\u0026thinsp;0.105).\u003c/p\u003e\u003cp\u003eA significant decrease in survival was noticed in both \u003cem\u003eAedes\u003c/em\u003e mosquito after all treatments such as 39\u0026deg;C\u0026times; 1.5 ppm, 40\u0026deg;C\u0026times; 1ppm and 40\u0026deg;C\u0026times; 1.5ppm. However, there was no such interaction found between temperature and Bti in survival rate. The F\u003csub\u003e1\u003c/sub\u003e progeny obtained from \u003cem\u003eAe. aegypti\u003c/em\u003e and \u003cem\u003eAe. albopictus\u003c/em\u003e treated at 39\u0026deg;C\u0026times; 0.5ppm, 39\u0026deg;C\u0026times; 1ppm did not show any significant difference in survival rate as compared to control. The survival rate is greatly reduced at 40\u0026deg;C\u0026times; 1ppm, 40\u0026deg;C\u0026times; 1.5ppm treatment. So, further study of F\u003csub\u003e1\u003c/sub\u003e progeny from larvae treated at these two respective doses were not carried out in the present study.\u003c/p\u003e\n\u003ch3\u003eFecundity\u003c/h3\u003e\n\u003cp\u003eThe mean total fecundity decreased significantly in both \u003cem\u003eAe. aegypti\u003c/em\u003e (F\u003csub\u003e2,12\u003c/sub\u003e=167.769 P\u0026thinsp;=\u0026thinsp;0.000) and \u003cem\u003eAe. albopictus\u003c/em\u003e (F\u003csub\u003e2,12\u003c/sub\u003e=219.547, P\u0026thinsp;=\u0026thinsp;0.000) derived from the thermally exposed larvae with the lowest fecundity observed at 40\u0026deg;C treated mosquito (Fig.\u0026nbsp;\u003cspan refid=\"Fig10\" class=\"InternalRef\"\u003e4\u003c/span\u003e). F\u003csub\u003e1\u003c/sub\u003e progeny obtained from thermally exposed larvae of both \u003cem\u003eAe. aegypti\u003c/em\u003e (F\u003csub\u003e2,12\u003c/sub\u003e=3.376, P\u0026thinsp;=\u0026thinsp;0.069) and \u003cem\u003eAe. albopictus\u003c/em\u003e (F\u003csub\u003e2,12\u003c/sub\u003e=3.104, P\u0026thinsp;=\u0026thinsp;0.82) did not show any difference in rate of fecundity.\u003c/p\u003e\u003cp\u003eLike temperature exposed mosquito the mean total fecundity decreased significantly in \u003cem\u003eAe. aegypti\u003c/em\u003e (F\u003csub\u003e2,12\u003c/sub\u003e=1180.477, P ˂ 0.001) and \u003cem\u003eAe. albopictus\u003c/em\u003e (F\u003csub\u003e2,12\u003c/sub\u003e= 474.641, P ˂ 0.001) females derived from the Bti exposed larvae than control set. F\u003csub\u003e1\u003c/sub\u003e progeny obtained from Bti exposed larvae of both \u003cem\u003eAe. aegypti\u003c/em\u003e (F\u003csub\u003e2,12\u003c/sub\u003e= 1522.667, P ˂ 0.001) and \u003cem\u003eAe. albopictus\u003c/em\u003e (F\u003csub\u003e2,12\u003c/sub\u003e= 2194.667, P ˂ 0.001 ) show a significant difference in rate of fecundity.\u003c/p\u003e\u003cp\u003eThe fecundity of both \u003cem\u003eAedes\u003c/em\u003e mosquito significantly decreased when treated with 39\u0026deg;C\u0026times; 1ppm, 39\u0026deg;C\u0026times; 1.5 ppm, 40\u0026deg;C\u0026times; 1ppm, 40\u0026deg;C\u0026times; 1.5 ppm in a dose-dependent manner from the control group. A significant impact (\u003csub\u003eF1, 20\u003c/sub\u003e = 14.970, P\u0026thinsp;=\u0026thinsp;0.001) of temperature and Bti interaction on rate of fecundity was noticed in \u003cem\u003eAe. albopictus\u003c/em\u003e but no such interaction was detected in \u003cem\u003eAe. aegypti\u003c/em\u003e. Fecundity of F\u003csub\u003e1\u003c/sub\u003e progeny did not differ significantly from control.\u003c/p\u003e\u003cdiv id=\"Sec11\" class=\"Section2\"\u003e\u003ch2\u003eSex ratio\u003c/h2\u003e\u003cp\u003eThe results indicate a significantly higher proportion of emergence of females in both \u003cem\u003eAe. aegypti\u003c/em\u003e (F\u003csub\u003e2,12\u003c/sub\u003e=100.667, P\u0026thinsp;=\u0026thinsp;0.000) and \u003cem\u003eAe. albopictus\u003c/em\u003e (F\u003csub\u003e2,12\u003c/sub\u003e= 68.625, P\u0026thinsp;=\u0026thinsp;0.000) exposed to temperature stress than in control set (Fig .3). The largest difference in sex ratio was noticed in the group of \u003cem\u003eAe. aegypti\u003c/em\u003e and \u003cem\u003eAe. albopictus\u003c/em\u003e which were exposed at 40\u0026deg;C. A significant increase in sex ratio was found between 39\u0026deg;C and 40\u0026deg;C treatment. The F\u003csub\u003e1\u003c/sub\u003e progeny obtained from \u003cem\u003eAe. aegypti\u003c/em\u003e and \u003cem\u003eAe. albopictus\u003c/em\u003e treated at 39\u0026deg;C\u0026times; 0.5ppm, 39\u0026deg;C\u0026times; 1ppm did not show any significant difference in sex ratio as compared to control set.\u003c/p\u003e\u003cp\u003eThe results indicate a significantly higher proportion of males in both \u003cem\u003eAe. aegypti\u003c/em\u003e (F\u003csub\u003e2,12\u003c/sub\u003e=70.679, P\u0026thinsp;=\u0026thinsp;0.000 ) and \u003cem\u003eAe. albopictus\u003c/em\u003e (F\u003csub\u003e2,12\u003c/sub\u003e=144.440, P\u0026thinsp;=\u0026thinsp;0.000 ) exposed to Bti. The largest difference in sex ratio was noticed in the group of \u003cem\u003eAe. aegypti\u003c/em\u003e and \u003cem\u003eAe. albopictus\u003c/em\u003e exposed to 1.5 ppm of Bti. The sex ratio did not differ among individuals exposed to different sublethal concentrations of Bti. It was noticed that Bti larvicide influenced the sex ratio while comparing the results of sublethal conc. with that of control.\u003c/p\u003e\u003cp\u003eMore female emerged in \u003cem\u003eAe. aegypti\u003c/em\u003e mosquito at 40\u0026deg;C\u0026times; 1ppm, 40\u0026deg;C\u0026times; 1.5ppm treatment in \u003cem\u003eAe. aegypti\u003c/em\u003e mosquito and no significant interaction was found between temperature and Bti (F\u003csub\u003e1,20\u003c/sub\u003e=3.866, P\u0026thinsp;=\u0026thinsp;.063). Whereas in \u003cem\u003eAe. albopictus\u003c/em\u003e the number of female increased at 39\u0026deg;C\u0026times; 1.5ppm, 40\u0026deg;C\u0026times; 1ppm, 40\u0026deg;C\u0026times; 1.5ppm treatment and no significant interaction between temperature and Bti (F1,20\u0026thinsp;=\u0026thinsp;5.578, P\u0026thinsp;=\u0026thinsp;0.058) was observed for this trait. The F\u003csub\u003e1\u003c/sub\u003e progeny of \u003cem\u003eAe. aegypti\u003c/em\u003e (F\u003csub\u003e2,12\u003c/sub\u003e=3.339, P\u0026thinsp;=\u0026thinsp;0.070 ) and \u003cem\u003eAe. albopictus\u003c/em\u003e (F\u003csub\u003e2,12\u003c/sub\u003e=3.824, P\u0026thinsp;=\u0026thinsp;0.052) exposed to 39\u0026deg;C\u0026times; 0.5ppm, 39\u0026deg;C\u0026times; 1ppm did not show any significant difference in sex ratio.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec12\" class=\"Section2\"\u003e\u003ch2\u003eHatchability rate\u003c/h2\u003e\u003cp\u003eThe proportion of larvae hatched from the eggs derived from both \u003cem\u003eAe. aegypti\u003c/em\u003e (F\u003csub\u003e2,12\u003c/sub\u003e=135.135, P\u0026thinsp;=\u0026thinsp;0.000) and \u003cem\u003eAe. albopictus\u003c/em\u003e (F\u003csub\u003e2,12\u003c/sub\u003e=112.690, P\u0026thinsp;=\u0026thinsp;0.000) exposed to temperature stress decreased significantly from control (Fig.\u0026nbsp;\u003cspan refid=\"Fig11\" class=\"InternalRef\"\u003e5\u003c/span\u003e). The F\u003csub\u003e1\u003c/sub\u003e progeny of \u003cem\u003eAedes\u003c/em\u003e mosquito treated with temperature at 39\u0026deg;C and 40\u0026deg;C did not show any significant difference in hatchability except in F\u003csub\u003e1\u003c/sub\u003e progeny of \u003cem\u003eAe. albopictus\u003c/em\u003e (F\u003csub\u003e2,12\u003c/sub\u003e=15.505, P\u0026thinsp;=\u0026thinsp;0.001) treated at 40\u0026deg;C which showed a significant decrease in hatchability.\u003c/p\u003e\u003cp\u003eThe results also indicated that the hatchability of eggs was significantly decreased after Bti exposure in both \u003cem\u003eAe. aegypti\u003c/em\u003e (F\u003csub\u003e2,12\u003c/sub\u003e=244.556, P\u0026thinsp;=\u0026thinsp;0.000 ) and \u003cem\u003eAe. albopictus\u003c/em\u003e (F\u003csub\u003e2,12\u003c/sub\u003e=54.319, P\u0026thinsp;=\u0026thinsp;0.000) in dose dependent manner. Further, the hatchability of eggs was significantly decreased in the F\u003csub\u003e1\u003c/sub\u003e progeny of Bti exposed \u003cem\u003eAe. aegypti\u003c/em\u003e (F\u003csub\u003e2,12\u003c/sub\u003e=157.930, P ˂ 0.001) and \u003cem\u003eAe. albopictus\u003c/em\u003e (F\u003csub\u003e2,12\u003c/sub\u003e=117.875, P = ˂ 0.001).\u003c/p\u003e\u003cp\u003eThe hatchability significantly decreased in both \u003cem\u003eAedes\u003c/em\u003e at 39\u0026deg;C\u0026times; 1.5ppm and significantly increased from control at 39\u0026deg;C\u0026times; 1ppm treatment in \u003cem\u003eAe. albopictus\u003c/em\u003e. However, hatchability reduced nearly to zero in both \u003cem\u003eAedes\u003c/em\u003e treated at 40\u0026deg;C\u0026times; 1ppm, 40\u0026deg;C\u0026times; 1.5ppm respectively. The hatchability of F\u003csub\u003e1\u003c/sub\u003e progeny of both \u003cem\u003eAedes\u003c/em\u003e treated at 39\u0026deg;C\u0026times; 1ppm and 39\u0026deg;C\u0026times; 1.5 ppm did not differ significantly from control.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec13\" class=\"Section2\"\u003e\u003ch2\u003eLongevity\u003c/h2\u003e\u003cp\u003eSignificant decrease in longevity of both \u003cem\u003eAe. aegypti\u003c/em\u003e (F\u003csub\u003e2,9\u003c/sub\u003e=8.485, P\u0026thinsp;=\u0026thinsp;0.008 ) and \u003cem\u003eAe. albopictus\u003c/em\u003e (F\u003csub\u003e2,9\u003c/sub\u003e=23.661, P ˂0.001) was observed in mosquitoes exposed to temperature stress (40\u0026deg;C) (Fig.\u0026nbsp;\u003cspan refid=\"Fig12\" class=\"InternalRef\"\u003e6\u003c/span\u003e). F\u003csub\u003e1\u003c/sub\u003e progeny obtained from thermally exposed larvae of both \u003cem\u003eAe. aegypti\u003c/em\u003e and \u003cem\u003eAe. albopictus\u003c/em\u003e did not show any significant difference in the rate of longevity.\u003c/p\u003e\u003cp\u003eSimilarly the longevity decreased significantly in \u003cem\u003eAe. aegypti\u003c/em\u003e (F\u003csub\u003e2,9\u003c/sub\u003e=35.237, P\u0026thinsp;=\u0026thinsp;0.008) and \u003cem\u003eAe. albopictus\u003c/em\u003e (F\u003csub\u003e2,9\u003c/sub\u003e=21.553, P ˂0.001) treated with Bti (1.0 and 1.5 ppm). F\u003csub\u003e1\u003c/sub\u003e progeny obtained from Bti exposed larvae of both \u003cem\u003eAe. aegypti\u003c/em\u003e and \u003cem\u003eAe. albopictus\u003c/em\u003e did not show any significant difference in the rate of longevity. The longevity increased in \u003cem\u003eAe. aegypti\u003c/em\u003e adult derived from larvae exposed to 39\u0026deg;C\u0026times; 1ppm, 39\u0026deg;C\u0026times; 1.5 ppm and decreased in adult derived from larvae exposed to 40\u0026deg;C\u0026times; 1ppm, 40\u0026deg;C\u0026times; 1.5 ppm. However, the longevity decreased in adult derived from larvae of \u003cem\u003eAe. albopictus\u003c/em\u003e in 39\u0026deg;C\u0026times; 1ppm, 40\u0026deg;C\u0026times; 1ppm, 40\u0026deg;C\u0026times; 1.5 ppm and increased non significantly at 39\u0026deg;C\u0026times; 1.5 ppm treatment respectively. F\u003csub\u003e1\u003c/sub\u003e progeny obtained from larvae of both \u003cem\u003eAe. aegypti\u003c/em\u003e and \u003cem\u003eAe. albopictus\u003c/em\u003e exposed to 39\u0026deg;C\u0026times; 1ppm, 39\u0026deg;C\u0026times; 1.5 ppm did not show any significant difference in rate of longevity.\u003c/p\u003e\u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003eThis study was undertaken to understand how the temperature stress and Bti influence life history traits of two important \u003cem\u003eAedes\u003c/em\u003e mosquito vectors \u003cem\u003eAedes aegypti\u003c/em\u003e and \u003cem\u003eAedes albopictus\u003c/em\u003e. Insects are ectotherms and environmental temperature greatly influences their survival, distribution, behavioral characteristics, life-history traits, and fitness (Cui et al., \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2008\u003c/span\u003e; Denlinger and Yocum, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e1998\u003c/span\u003e). When temperatures increase beyond an insect's optimal range, there are two conjointly exclusive consequences: survival or death (Denlinger and Yocum, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e1998\u003c/span\u003e). Even a species could survive after exposure to temperature stress but fitness could be affected (Rinehart et al., \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2000\u003c/span\u003e). Heat stress may cause the death of individuals by causing abnormalities at the cellular level due to changes in ion concentration and pH. Shortened development periods at higher temperatures reduce food supply and lead to death (Clements, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e1992\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eCurrent results showed that both \u003cem\u003eAedes\u003c/em\u003e species exhibited different responses to thermal exposure. A reduction in developmental time was noticed after thermal stress in \u003cem\u003eAedes\u003c/em\u003e mosquito. The survival rate decreased after thermal exposure in both \u003cem\u003eAedes\u003c/em\u003e mosquito species. The number of eggs deposited by both species of \u003cem\u003eAedes\u003c/em\u003e mosquito was significantly decreased after thermal exposure. Earlier study by many researchers showed that thermal stress can affect ovarian development and cause damage to oocytes in females and reduce the fertility of male by injuring testes and sperm that could lead to a decrease in egg production (Chihrane and Lauge, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e1994\u003c/span\u003e; \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e1997\u003c/span\u003e; Krebs and Loeschcke, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e1994\u003c/span\u003e; Rinehart et al., \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2000\u003c/span\u003e; Scott et al., \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e1997\u003c/span\u003e) which is similar to the current findings where hatchability was decreased in females obtained from thermally exposed larvae. More female emergence and lower longevity in thermally treated mosquito populations was noticed in the present study which is similar to the finding of Zhu et al., (\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e2017\u003c/span\u003e) on Bradysia. The F\u003csub\u003e1\u003c/sub\u003e progeny derived from thermally exposed \u003cem\u003eAedes\u003c/em\u003e mosquito did not showed any significant difference in all life history traits. We didn\u0026rsquo;t observe any significant difference in developmental time of F\u003csub\u003e1\u003c/sub\u003e progeny derived from thermally exposed \u003cem\u003eAedes\u003c/em\u003e mosquito. The survival of F\u003csub\u003e1\u003c/sub\u003e progeny obtained from thermally exposed \u003cem\u003eAedes\u003c/em\u003e increased as compared to control. An increased fecundity and hatchability rate in progeny obtained from thermally exposed \u003cem\u003eAe. aegypti\u003c/em\u003e and \u003cem\u003eAe. albopictus\u003c/em\u003e was noticed in the present study from their parent. Sex ratio showed no significant difference in the F\u003csub\u003e1\u003c/sub\u003e progeny derived from thermally exposed \u003cem\u003eAedes\u003c/em\u003e mosquito from control.\u003c/p\u003e\u003cp\u003eThe incidence of dengue has grown dramatically in few decades worldwide. About half of the world's population is now at risk (WHO, \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). So it is important to control its mosquito vector population. Further, the control of mosquito vector population during their immature stage is much easier as compared to adult stage as the movement of the larvae is restricted to its aquatic habitat. Sub-lethal effect is prolonging the developmental period of larvae which will support the chances of killing the larvae more in the aquatic habitat.\u003c/p\u003e\u003cp\u003eIn present study, Bti exposure did not show any significant difference from control in developmental period after exposure to Bti, which is similar to the findings of Flores et al., (\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2004\u003c/span\u003e). Mortality in larvae increased as the concentration of Bti increased which is in agreement with the results of Saleh and Wright (\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e1989\u003c/span\u003e). In the present study, it was observed that the number of females was reduced with Bti treatments in exposed \u003cem\u003eAedes\u003c/em\u003e mosquito. It appears that immatures fated to be females are more prone to the Bti effect, indicating the effects of the toxin on larvae before pupation, resulting in ratios tilted towards males. So the use of Bti is advantageous because there would be a decrease in the reproductive population in the treated area which is similar to the findings of Flores et al., (\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2004\u003c/span\u003e) on \u003cem\u003eAedes aegypti\u003c/em\u003e. Saleh et al., (\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e1990\u003c/span\u003e) on the contrary found more females than males in the treatment groups. Reproductive potential of \u003cem\u003eAedes\u003c/em\u003e mosquito was significantly reduced after Bti exposure which is similar to the findings of Saleh et al., (\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e1990\u003c/span\u003e). A decrease in longevity of adults obtained from Bti exposed larvae were also found which was similar to the finding of Saleh et al., (\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e1990\u003c/span\u003e). This may be because of a flagging action on the physiology of larvae and subsequently affecting the longevity of surviving adults. In present study, Bti exposure showed significant difference in developmental period of F\u003csub\u003e1\u003c/sub\u003e progeny from control which is similar to the findings of Flores et al., (\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2004\u003c/span\u003e). A decrease in the survival rate (although not significant) was found in F\u003csub\u003e1\u003c/sub\u003e progeny of Bti exposed \u003cem\u003eAedes\u003c/em\u003e observed with exception to F\u003csub\u003e1\u003c/sub\u003e derived from \u003cem\u003eAe. aegypti\u003c/em\u003e treated at 1.0 ppm Bti and F\u003csub\u003e1\u003c/sub\u003e derived from \u003cem\u003eAe. albopictus\u003c/em\u003e treated at 1.5 ppm of Bti. Reproductive potential of \u003cem\u003eAedes\u003c/em\u003e mosquito was significantly reduced in F\u003csub\u003e1\u003c/sub\u003e progeny derived from Bti exposed parent. This is contrary to the findings of Saleh et al., (\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e1990\u003c/span\u003e) where Bti treatment reduces the reproductive potential of \u003cem\u003eCulex pipiens\u003c/em\u003e in the first generation (treated) but remain unchanged in their progeny.\u003c/p\u003e\u003cp\u003eThe developmental period showed non-significant difference in larvae exposed to 39\u0026deg;C\u0026times; 0.5ppm, 39\u0026deg;C\u0026times; 1ppm, 40\u0026deg;C\u0026times; 0.5ppm, 40\u0026deg;C\u0026times; 1ppm. However, a significant decrease in survival rate was noticed in both \u003cem\u003eAedes\u003c/em\u003e mosquito after all treatments such as 39\u0026deg;C\u0026times; 1ppm, 39\u0026deg;C\u0026times; 1.5 ppm, with high reduction at 40\u0026deg;C\u0026times; 1ppm and 40\u0026deg;C\u0026times; 1.5ppm. More female emergence was observed in \u003cem\u003eAe. aegypti\u003c/em\u003e mosquito in 40\u0026deg;C\u0026times; 1ppm, 40\u0026deg;C\u0026times; 1.5ppm treatment and in \u003cem\u003eAe. albopictus\u003c/em\u003e, the number of female increases at 39\u0026deg;C\u0026times; 1.5ppm, 40\u0026deg;C\u0026times; 1ppm, 40\u0026deg;C\u0026times; 1.5ppm treatment. The fecundity of both \u003cem\u003eAedes\u003c/em\u003e mosquito significantly decreased when treated with at 39\u0026deg;C\u0026times; 1ppm, 39\u0026deg;C\u0026times; 1.5 ppm, 40\u0026deg;C\u0026times; 1ppm, 40\u0026deg;C\u0026times; 1.5 ppm in a dose-dependent manner. The hatchability significantly decreased in both \u003cem\u003eAedes\u003c/em\u003e at 39\u0026deg;C\u0026times; 1.5ppm and significantly increased from control at 39\u0026deg;C\u0026times; 1ppm treatment. However, hatchability reduced nearly to zero in both \u003cem\u003eAedes\u003c/em\u003e mosquito treated at 40\u0026deg;C\u0026times; 1ppm, 40\u0026deg;C\u0026times; 1.5ppm. The longevity increased in \u003cem\u003eAe. aegypti\u003c/em\u003e adult derived from larvae exposed to 39\u0026deg;C\u0026times; 1ppm, 39\u0026deg;C\u0026times; 1.5 ppm and decreased in larvae exposed to 40\u0026deg;C\u0026times; 1ppm, 40\u0026deg;C\u0026times; 1.5 ppm. However, the longevity decreased in adult derived from larvae of \u003cem\u003eAe. albopictus\u003c/em\u003e in 39\u0026deg;C\u0026times; 1ppm, 40\u0026deg;C\u0026times; 1ppm, 40\u0026deg;C\u0026times; 1.5 ppm and increased non significantly at 39\u0026deg;C\u0026times; 1.5 ppm treatment. The developmental period of F\u003csub\u003e1\u003c/sub\u003e progeny derived from mosquito treated at 39\u0026deg;C\u0026times; 1ppm, 39\u0026deg;C\u0026times; 1.5ppm showed a significant difference in any life history traits.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eIn the present study, it has been observed that temperature and Bti significantly influence the behavioral traits in \u003cem\u003eAedes\u003c/em\u003e mosquito. Temperature stress imparts negative influence on \u003cem\u003eAedes\u003c/em\u003e mosquito by decreasing survival, longevity and reproductive potential while it imparts some positive effects like decreasing developmental period and producing more female offspring which can increase mosquito population and transmission of pathogens (as female mosquito carry pathogen). Similarly, Bti alone affects most of the life history traits beyond the parental generation. However, temperature stress alone and the combined effect (or interaction) of both stress do not affect the life history traits significantly in F\u003csub\u003e1\u003c/sub\u003e generation. Bti exposure increased the developmental period, reduced reproductive potential of the \u003cem\u003eAedes\u003c/em\u003e mosquito in F\u003csub\u003e1\u003c/sub\u003e generation. Therefore, it may be concluded that Bti can be used as an effective tool for \u003cem\u003eAedes\u003c/em\u003e mosquito vector control. Temperature and Bti in combination reduce survival rate and reproductive potential in \u003cem\u003eAedes\u003c/em\u003e mosquito. Consequently, it appears that while global warming may cause an increase in dengue transmission, based on the current findings, Bti can be used for dengue prevention and control in the current climatic condition.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003eNot applicable\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eData generated during this study are included in this published article\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study had no funding.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors’ contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eTSA executed the experiment and carried out data analysis and manuscript writing, TKB designed the experiment, carried out data analysis. Both the authors have read and approved the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe would like to thank to the head, Post Graduate Department of Zoology, Berhampur University, Berhampur, Odisha, for providing necessary facilities and encouragement.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor details\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003csup\u003e1\u003c/sup\u003ePost-Graduate Department of Zoology, Berhampur University, Berhampur-760007, Odisha, India.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eAchari, T.S., Acharya, U.R., Barik, T.K. (2017). Impact of thermal stress on survival and induced cross-tolerance to toxins of \u003cem\u003eBacillus thuringiensis\u003c/em\u003e in wild \u003cem\u003eAedes aegypti\u003c/em\u003e. International Journal of Bioscience, 11,156\u0026ndash;164. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.12692/ijb/11.1.156-164\u003c/span\u003e\u003cspan address=\"10.12692/ijb/11.1.156-164\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eAchari, T.S., Barik, T.K. (2019). Assessment of Temperature-induced Cross-tolerance to \u003cem\u003eBacillus thuringiensis\u003c/em\u003e subsp. \u003cem\u003eisraelensis\u003c/em\u003e on Field-collected \u003cem\u003eAedes albopictus\u003c/em\u003e. Biopestice International, 15, 97\u0026ndash;104.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eAlto, B.W., Bettinardi, D. (2013). Temperature and dengue virus infection in mosquitoes: independent effects on the immature and adult stages. American Journal of Tropical Medicine and Hygiene, 88(3), 497\u0026ndash;505. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.4269/ajtmh.12-0421\u003c/span\u003e\u003cspan address=\"10.4269/ajtmh.12-0421\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eBriegel, H., Knusel, I., Timmermann, S.E. (2001). \u003cem\u003eAedes aegypti\u003c/em\u003e: size, reserves, survival, and flight potential. Journal of Vector Ecology, 26(1), 21\u0026ndash;31.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eBriegel, H., Timmermann, S.E. (2001). \u003cem\u003eAedes albopictus\u003c/em\u003e (Diptera: Culicidae): physiological aspects of development and reproduction. Journal of Medical Entomology, 38(4), 566\u0026ndash;571.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eBriegel, H., Waltert, A., Kuhn, R. (2000). Reproductive physiology of \u003cem\u003eAedes\u003c/em\u003e (Aedimorphus) \u003cem\u003evexans\u003c/em\u003e (Diptera: Culicidae) in relation to flight potential. Journal of Medical Entomology, 38(4), 557\u0026ndash;565. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1603/0022-2585-38.4.557\u003c/span\u003e\u003cspan address=\"10.1603/0022-2585-38.4.557\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eChihrane, J., Lauge, G. (1994). Effects of high-temperature shocks on male germinal cells of \u003cem\u003eTrichogramma brassicae\u003c/em\u003e (Hymenoptera, Trichogrammatidae). Entomophaga, 39(1), 11\u0026ndash;20.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eChihrane, J., Lauge, G. (1997). Thermosensitivity of germ lines of \u003cem\u003eTrichogramma brassicae\u003c/em\u003e Bezdenko (Hymenoptera) - implications for efficacy of the parasitoid. Canadian Journal of Zoology, 75, 484\u0026ndash;489.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eClements, A.N. (1992). The biology of mosquitoes: Development, nutrition and reproduction, p.150\u0026ndash;170. In A.N.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eCui, X., Wan, F., Xie, M., and Liu, T. (2008). Effects of Heat Shock on Survival and Reproduction of Two Whitefly Species, \u003cem\u003eTrialeurodes vaporariorum\u003c/em\u003e and \u003cem\u003eBemisia tabaci\u003c/em\u003e Biotype B. Journal of Insect Science, 8(24),1\u0026ndash;10.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eDenlinger, D.L., Yocum, G.D. (1998). Physiology of heat sensitivity. In: Hallman GJ, Denlinger DL, editors. Thermal sensitivity in insects and application in integrated pest management 11\u0026ndash;18. Westview Press, Boulder, Colorado, USA.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eDixit, V., Gupta, A.K., Kataria, O., Prasad, G.B.K.S. (2002). Population dynamics of \u003cem\u003eCulex quinquefasciatus\u003c/em\u003e filaria vector in Raipur City of Chhattisgarh State. Journal of Communicable Diseases, 34(3), 193\u0026ndash;202.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eFlipse, J. and Smit, J.M. (2015). The Complexity of a Dengue Vaccine: A Review of the Human Antibody Response. PLOS Neglected Tropical Diseases, 9(6), e0003749.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eFlores, A.E., Garcia, G.P., Badii, M.H., Rodriguez Tovar, M.A., Fernandez Salas, I. (2004). Effects of sublethal concentrations of Vectobac on biological parameters of \u003cem\u003eAedes aegypti\u003c/em\u003e. Journal of the American Mosquito Control Association, 20(4), 412\u0026ndash;417.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eGlunt, K.D., Blanford, J.I., Paaijmans, K.P. (2013). Chemicals, climate, and control: increasing the effectiveness of malaria vector control tools by considering relevant temperatures. \u003cem\u003ePLOS Pathogens\u003c/em\u003e, 9 (10), p. e1003602, \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1371/journal.-ppat.1003602\u003c/span\u003e\u003cspan address=\"10.1371/journal.-ppat.1003602\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eGray, K.M., Burkett-Cadena, N.D., Eubanks, MD, Unnasch TR (2011). Crepuscular flight activity of \u003cem\u003eCulex erraticus\u003c/em\u003e (Diptera: Culicidae). Journal of Medical Entomology, 48(2), 167\u0026ndash;172. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1603/me10176\u003c/span\u003e\u003cspan address=\"10.1603/me10176\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eHelinski, M.E.H., Parker, A.G., Knols, B.G.J. (2009). Radiation biology of mosquitoes. Malaria Journal, 8(Suppl. 2), S6. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1186/1475-2875-8-S2-S6\u003c/span\u003e\u003cspan address=\"10.1186/1475-2875-8-S2-S6\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eKrebs, R.A., Loeschcke, V. (1994). Effects of exposure to short-term heat stress on fitness components in \u003cem\u003eDrosophila melanogaster\u003c/em\u003e. Journal of Evolutionary Biology, 7(1), 39\u0026ndash;49. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1046/j.1420-9101.1994.7010039.x\u003c/span\u003e\u003cspan address=\"10.1046/j.1420-9101.1994.7010039.x\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLacey, L.A. (2007). \u003cem\u003eBacillus thuringiensis\u003c/em\u003e serovariety \u003cem\u003eisraelensis\u003c/em\u003e and \u003cem\u003eBacillus sphaericus\u003c/em\u003e for mosquito control. Journal of the American Mosquito Control, 23(2), 133\u0026ndash;163. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.2987/8756-971x\u003c/span\u003e\u003cspan address=\"10.2987/8756-971x\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e(2007)23[133:btsiab]2.0.co;2\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMeyer, R.P., Hardy, J.L., Reisen, W.K. (1990). Diel changes in adult mosquito microhabitat temperatures and their relationship to the extrinsic incubation of arbovirues in mosquitoes in Kern County, California. Journal of Medical Entomology, 27(4), 607\u0026ndash;614. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1093/jmedent/27.4.607\u003c/span\u003e\u003cspan address=\"10.1093/jmedent/27.4.607\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eRinehart, J.P., Yocum, G.D., Denlinger, D.L. (2000). Thermotolerance and rapid cold hardening ameliorate the negative effects of brief exposures to high or low temperatures on fecundity in the flesh fly, \u003cem\u003eSarcophaga crassipalpis\u003c/em\u003e. Physiological Entomology, 25(4), 330\u0026ndash;336. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1111/j.1365-3032.2000.00201.x\u003c/span\u003e\u003cspan address=\"10.1111/j.1365-3032.2000.00201.x\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eRohr, J.R., Schotthoefer, A.M., Raffel, T.R., Carrick, H.J., Halstead, N., Hoverman, J.T., Johnson, C.M., Johnson, L.B., Lieske, C., Piwoni, M.D., Schoff, P.K. and Beasley, V.R. (2008). Agrochemicals increase trematode infections in a declining amphibian species. Nature 455, 1235\u0026ndash;1239. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1038/nature07281\u003c/span\u003e\u003cspan address=\"10.1038/nature07281\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eRowley, W.A., Graham, C.L. (1968). The effect of temperature and relative humidity on the flight performance of female \u003cem\u003eAedes aegypti\u003c/em\u003e. Journal of Insect Physiology, 14(9), 1251\u0026ndash;1257. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/0022-1910(68)90018-8\u003c/span\u003e\u003cspan address=\"10.1016/0022-1910(68)90018-8\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSaleh, M.S., Kelada, N.L., and Abdeen, M.I. (1990). The delayed effects of \u003cem\u003eBacillus thuringiensis\u003c/em\u003e H-14 on the reproductive potential and subsequent larval development of the mosquito \u003cem\u003eCulex pipiens\u003c/em\u003e L. Journal of Applied Entomology, 109(1\u0026ndash;5), 520\u0026ndash;523.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSaleh, M.S., Wright, R.E. (1989). Effects of the IGR cyromazine and the pathogen \u003cem\u003eBacillus thuringiensis\u003c/em\u003e var. \u003cem\u003eisraelensis\u003c/em\u003e on the mosquito \u003cem\u003eAedes epucticus\u003c/em\u003e. Journal of Applied Entomology, 108(4), 381\u0026ndash;385. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttp://dx.doi.org/10.1111/j.1439-0418.1989.tb00471.x\u003c/span\u003e\u003cspan address=\"10.1111/j.1439-0418.1989.tb00471.x\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSandland, G.J., and Carmosini, N. (2006). Combined effects of a herbicide (atrazine) and predation on the life history of a pond snail, Physa gyrina. Environmental Toxicology and Chemistry, 25(8), 2216\u0026ndash;2220. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1897/05-596R.1\u003c/span\u003e\u003cspan address=\"10.1897/05-596R.1\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eScott, M., Berrigan, D., Hoffmann, A.A. (1997). Costs and benefits of acclimation to elevated temperature in \u003cem\u003eTrichogramma carverae\u003c/em\u003e. Entomologia Experimentalis et Applicata, 85(3), 211\u0026ndash;219. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1046/j.1570-7458.1997.00251.x\u003c/span\u003e\u003cspan address=\"10.1046/j.1570-7458.1997.00251.x\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSwain, V., Seth, R.K., Mohanty, S.S., Raghavendra, K. (2008). Effect of temperature on development, eclosion, longevity and survivorship of malathion-resistant and malathion-susceptible strain of \u003cem\u003eCulex quinquefasciatus\u003c/em\u003e. Parasitology Research, 103(2), 299\u0026ndash;303. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s00436-008-0969-5\u003c/span\u003e\u003cspan address=\"10.1007/s00436-008-0969-5\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eWeis, J.S., Smith, G., Zhou, T., Santiago-Bass, C., and Weis, P. (2001). Effects of contaminants on behavior: Biochemical mechanisms and ecological consequences. Bioscience, 51(3), 209\u0026ndash;217. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1641/0006-3568(2001)051[0209:EOCOBB]2.0.CO;2\u003c/span\u003e\u003cspan address=\"10.1641/0006-3568(2001)051[0209:EOCOBB]2.0.CO;2\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eWHO (1988). Environmental Management for Vector Control. Training and informational materials slides set series. \u003cem\u003eWorld health organization\u003c/em\u003e. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttp://helid.digicollection.org/en/d/Jwhow01e/\u003c/span\u003e\u003cspan address=\"http://helid.digicollection.org/en/d/Jwhow01e/\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. Accessed on 18.6.2021\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eWHO (2006). Guidelines for testing mosquito adulticides for indoor residual spraying and treatment of mosquito nets. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://apps.who.int/iris/handle/10665/69296\u003c/span\u003e\u003cspan address=\"https://apps.who.int/iris/handle/10665/69296\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. Accessed on 18.6.2021\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eWHO (2020). Vector borne disease factsheet. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.who.int/news-room/fact-sheets/detail/vector-borne-diseases\u003c/span\u003e\u003cspan address=\"https://www.who.int/news-room/fact-sheets/detail/vector-borne-diseases\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. Accessed on 2.3.2020\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eWright, R.E. and Knight, K.L. (1966). Effect of environmental factors on biting activity of \u003cem\u003eAedes vexans\u003c/em\u003e (Meigen) and \u003cem\u003eAedes trivittatus\u003c/em\u003e (Coquillett). Mosquito News, 26(4), 565\u0026ndash;578.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eZhu, G., Xue, M., Luo, Y., Ji, G., Liu, F., Zhao, H. and Sun, X. (2017). Effects of short-term heat shock and physiological responses to heat stress in two Bradysia adults, \u003cem\u003eBradysia odoriphaga\u003c/em\u003e and \u003cem\u003eBradysia difformis\u003c/em\u003e. Scientific Reports, 7, 13381. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1038/s41598-017-13560-4\u003c/span\u003e\u003cspan address=\"10.1038/s41598-017-13560-4\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Temperature, Aedes aegypti, Aedes albopictus, Bacillus thuringiensis israelensis, Life history traits","lastPublishedDoi":"10.21203/rs.3.rs-6635876/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6635876/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e\u003cp\u003eTemperature changes are common in nature and insects are particularly exposed to such variations which can be potential stresses, ultimately affecting life history traits and overall fitness. Here, we assessed the life history parameters of \u003cem\u003eAedes aegypti\u003c/em\u003e and \u003cem\u003eAedes albopictus\u003c/em\u003e when its larval stages were exposed to high temperatures (39\u0026deg;C, 40\u0026deg;C) and Bti (1 ppm and 1.5 ppm). The effects of both temperature and Bti were evaluated on the treated \u003cem\u003eAedes\u003c/em\u003e (F\u003csub\u003e0\u003c/sub\u003e) (immediate effects) and on their first generation (F\u003csub\u003e1\u003c/sub\u003e) progeny (trans-generational effects).\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e\u003cp\u003eIn the present study, it has been observed that temperature and Bti significantly influence the behavioral traits in both \u003cem\u003eAedes\u003c/em\u003e mosquito species. Temperature stress imparts negative influence on \u003cem\u003eAedes\u003c/em\u003e mosquito by decreasing survival, longevity and reproductive potential while it imparts some positive effects like decreasing developmental period and producing more female offspring which can increase mosquito population and transmission of pathogens. Bti alone affects most of the life history traits beyond the parental generation. However, temperature stress alone and the combined effect of both stress do not affect the life history traits significantly in F\u003csub\u003e1\u003c/sub\u003e generation. Bti exposure increased the developmental period, reduced reproductive potential of the \u003cem\u003eAedes\u003c/em\u003e mosquito in F\u003csub\u003e1\u003c/sub\u003e generation.\u003c/p\u003e\u003ch2\u003eConclusions\u003c/h2\u003e\u003cp\u003eTherefore, it may be concluded that Bti can be used as an effective tool for \u003cem\u003eAedes\u003c/em\u003e mosquito vector control. Temperature and Bti in combination reduce survival rate and reproductive potential in \u003cem\u003eAedes\u003c/em\u003e mosquito. Consequently, it appears that while global warming may cause an increase in dengue transmission, based on the current findings, Bti can be used for dengue prevention and control in the changing climatic condition.\u003c/p\u003e","manuscriptTitle":"Effects of temperature and Bacillus thuringiensis israelensis on life history traits of Aedes aegypti and Aedes albopictus mosquito species","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-09-16 18:43:39","doi":"10.21203/rs.3.rs-6635876/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"2fdd982d-0936-4141-b5b2-51686e7356b3","owner":[],"postedDate":"September 16th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-05-13T18:08:56+00:00","versionOfRecord":[],"versionCreatedAt":"2025-09-16 18:43:39","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6635876","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6635876","identity":"rs-6635876","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}